When President Donald Trump announced the selection of Lt. Gen. H.R. McMaster as his new national security advisor, I thought back to my days as a young lieutenant in 1991. I served as then-Capt. McMaster’s fire support officer in Eagle Troop, 2nd U.S. Cavalry, and I observed first-hand his outstanding leadership qualities at the Battle of 73 Easting, in which McMaster’s nine tanks and 12 Bradley Fighting Vehicles utterly destroyed an Iraqi Republican Guard armored brigade.

McMaster is among the most accomplished men in uniform today, but his new job provides a greater challenge than any he’s ever faced. He must work to guide American foreign policy at a time when a course correction is long overdue.

McMaster’s qualifications as an army leader are superb. His two major military operations were unqualified successes. When he took over Eagle Troop in 1990, the unit was dysfunctional, disheartened, and in poor shape. McMaster immediately infused it with focus, energy, and drive. After months of training, he led a confident Eagle Troop into the largest American tank battle since World War II, annihilating a brigade of the Iraqi Tawakalna Division. In 2005, U.S. forces in Iraq were foundering under the ravages of a full-blown insurgency. Then-Col. McMaster commanded the 3d Armored Cavalry Regiment, stationed in Nineveh Province near the violent, insurgent-filled city of Tal Afar. McMaster had trained his regiment on the basics of counter-insurgency prior to deployment. Working with political leaders of Tal Afar, his cavalry troopers succeeded in routing the insurgents and returned a sense of security to the city.

While McMaster’s tactical bona fides are beyond reproach, a national security advisor must be much more than an experienced combat leader. In normal times, it would be important to ensure that the person chosen to run the National Security Council has balanced experience set in both diplomatic and military affairs. But in the current Trump administration, it is doubly so.

This piece was originally published by War on the Rocks on March 3, 2017. Read the piece in its entirety HERE.

Daniel L. Davis is a Senior Fellow for Defense Priorities and a former Lt. Col. in the U.S. Army who retired in 2015 after 21 years, including four combat deployments.